1. Field of the Invention
This invention generally relates to the field of gold or gem mining, and more specifically to continuous flow sluice boxes.
2. Description of the Related Art
A number of methods are typically used to mine gold and gems from the earth's surface. In this disclosure, the material being mined will be referred to simply as “gold,” but other heavy metals, valuable materials and gems may still be includable in that term. This disclosure will also use the term “deposit material” to refer to the mix of gold and non-gold naturally found at a mining site. The simplest technique to separate gold from the non-gold material is panning. In panning some deposit material is placed in a large plastic or metal pan, along with a generous amount of water. The pan is then agitated so that the gold particles, being of higher density than the non-gold material, settle to the bottom. The non-gold material is flushed from the pan with the water, leaving the desired gold left in the bottom of the pan. Concentric, circumferential ribs are frequently added to the sides of the pan to provide additional low spots for the gold to settle during agitation.
The agitation in a pan can be circular or linear, and is caused by the motion of the pan in the hands of the miner. The waves created by the motion accelerate the non-gold particles, and keep them suspended, while the denser settle to the low spots in the pan.
Sluice boxes and rocker boxes work on a similar principle, just on a slightly larger scale. Rocker boxes tend to be slightly smaller, and both the deposit material and water are generally fed by hand. Improvements include using a filter blanket on the bottom of the box to capture the fine pieces of gold. Sluice boxes, as their name implies, are fed by a sluice, or water flow. Parallel ridges on the bottom of the sluice box, perpendicular to the flow of water, trap the heavier gold particles as the water washes them, while the non-gold material is removed with the water. The pitch of the sluice box and the rate of the water flow can be adjusted to optimize capture of the particular size of gold particles in the deposit material.
The side to side agitation of the rocker box, and the latter will slow agitation of the sluice box, both are seen to create horizontal swirls, or vortices, that agitate the deposit material. The non-gold material is accelerated in the swirled flow, and thereby continues to be suspended in the swirling water. The gold, however, because it is being denser, resists the swirling motion and settles in the low spots in the boxes.
It would be a valuable addition to the prior art to have a sluice box that avoids horizontal sluice riffles and matting, which rely on a horizontal vortex. Horizontal vortices easily become overloaded with heavy material and allow the loss of desired materials. Additionally, horizontal vortices at high flow rates can accelerate even the desired heavy material, such as gold, ejecting it with the runoff water. Further, traditional sluices require suspension of operation and dismantling in order to recover the collected gold, or clean the box after an overload. Such an addition, embodied in the current disclosure, lead to increased feed rates of material, optimum material separation and collection. Additionally, collection can be achieved while running the sluice box or if the box can be automated. Further, the current disclosure permits the owner to configure a sluice box system to secure gold laden collected materials in a locked container for periodic retrieval by authorized individuals.